Look at the HList stuff by Oleg and others and you'll find the kind of
tuples you suggest.
2009/2/17 Peter Verswyvelen
Tuples in Haskell always have annoyed me a bit since each tuple of different dimension is hardcoded (I guess compilers enforce a maximum dimension on tuples?) Since a tuple represents a fixed size data structure with different types at each coordinate, it feels as it should be possible to have a couple of type and data constructors to build a tuple, and to use recursion at the type level to have functions operate on tuples of any dimension. E.g. one could then have a tmap function that takes a tuple of functions and a tuple of values and applies the function at coordinate N to the value at coordinate N.
Is something like this possible today in Haskell, e.g. using new features like type families, GADTs, template haskell, etc? Or do we need dependent types for it? In C++x0 I believe it is now possible to do so, since they even allow a variable number of template arguments, using recursion at compile time (see e.g. http://publib.boulder.ibm.com/infocenter/comphelp/v9v111/index.jsp?topic=/co... ) Grapefruit has something like first class records, so I guess it should be possible (and simpler) to do this for tuples?
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